My project focuses on developing and validating an immunogenicity assay using electrochemiluminescence (ECL) technology to detect total antibodies against the adeno-associated virus (AAV) capsid. This assay is crucial for selecting patients for gene therapy clinical trials targeting Myotonic Dystrophy Type 1 (DM1). Pre-existing anti-AAV antibodies in patients can affect the safety and effectiveness of gene therapies using AAV vectors. We optimized assay parameters through repetitive testing to ensure robustness and accuracy, adhering to regulatory guidelines. This assay will help identify patients suitable for gene therapy trials by detecting pre-existing anti-AAV antibodies, ensuring safety and therapy efficacy assessments.